John Finnis (3 December 1802 – 13 August 1872), generally known as "Captain Finnis", was a seaman who is remembered for his association with Charles Sturt in the early days of South Australia.
Finnis was born in Dover, a son of Gilbert Finnis and his wife Elizabeth Finnis (née Nash). He qualified as a mariner, and after a few years as a working captain, in 1831 with Joseph Montefiore purchased the barque Elizabeth, in which he spent five successful years whaling in the southern seas.
In September 1838, he, with Captain Charles Sturt, Giles Strangways and George McLeod (a Norfolk Island friend of Sturt) brought 400 cattle overland from the Hume River. In 1839 Finnis, with Hampden Dutton and Duncan McFarlane, purchased 4000 acres (the Mount Barker Special Survey, the first such), to the chagrin of John Barton Hack, who was squatting there and had no intimation of the Special Survey. The land was used to fatten their cattle for sale, and settle 39 German families. brought to Australia by George Fife Angas on the Zebra (Captain Hahn) and Catharina (Captain Schecht). The following year he drove 10,000 sheep from New South Wales to Adelaide with Nelson and John Tooth, then supervised several later musters. Early in 1841 he and Frederick Dutton had another 12,000 sheep brought overland, which they offered for sale in March 1841, and also quantities of brandy, cigars and tobacco which they had brought by sea.
In 1843 he returned to the sea, chartering the Joseph Albino to bring goods from New Zealand and by the return journey export wheat and other commodities. He then purchased the ship and made other voyages, but the Joseph Albino was impounded in America with no redress.
He died at his home in Franklin Street, Adelaide.
In Sydney, on 23 March 1832, he married Ludovina Rosa Da Silva Cameron (1796 – 21 August 1854), the widow of Colonel Charles Cameron (1777–1827). Children of Rosa and Charles included: